With the continuing demand for smaller feature sizes in the semiconductor industry, 193 nm optical lithography has emerged very recently as the technology to produce devices with sub-100 nm features. The use of such a shorter wavelength of light requires the bottom antireflective coating (BARC) to reduce the reflection on substrate and dampen the photoresist swing cure by absorbing light that has passed though the photoresist. Commercially available antireflective coatings consist of both organic and inorganic based materials. Typically, the inorganic ARC, which exhibits good etch resistant, is CVD based and is subject to all the integration disadvantage of extreme topography; on the other hand, the organic ARC materials are applied by spin-on process and have excellent fill and planarization properties, but suffer from poor etch selectivity to organic photoresists. As a result, a material that offers the combined advantages of organic and inorganic ARC is highly desired.
In this regards, we have recently discovered that phenyl-hydride based silsesquioxane resins exhibit excellent anti-reflective coating properties for 193 nm light. This invention pertains to a new silsesquioxane material containing hydroxyl moiety, made via the co-hydrolysis of the corresponding chlorosilanes or alkoxysilanes. The hydroxyl moiety of the silane is protected by an organic group or a silyl group, which cleaves under the acidic conditions to yield the corresponding hydroxyl group. The new hydroxyl functional silsesquioxane resins form excellent spin-on film and has excellent PGMEA and TMAH resistance when cured at 250° C. or below.